Bone fixation system

ABSTRACT

A bone fixation system has a bone implant with an implant body. The implant body defines an upper surface, a bone-facing surface spaced from the upper surface along a transverse direction, and at least one aperture defined by an inner wall. A bone fixation element is configured for insertion at least partially through the aperture. The bone fixation element defines a proximal end and a distal end spaced from the proximal end along a central axis. The bone fixation element has a head and a shaft that extends relative to the head toward the distal end. The head defines a first ridge, a second ridge spaced from the first ridge, and a groove disposed between the first and second ridges. The groove can receive at least a portion of the inner wall to couple the bone fixation element to the bone implant.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.13/832,364 filed on Mar. 15, 2013 (now allowed) which claims the benefitof U.S. Provisional Application No. 61/692,673 filed Aug. 23, 2012, theentire disclosure of which is incorporated in this application byreference for all purposes.

TECHNICAL FIELD

The present disclosure relates to a bone fixation system, andparticularly to a bone implant and a bone fixation element, methods forcoupling a bone implant to a bone fixation element, and methods for bonefixation.

BACKGROUND

Bone implants are designed to help heal bone fractures and/or replacedamaged tissue. Principles that guide bone implant design includeanatomic reduction of fracture fragments, stable fixation to improvetissue healing, minimal procedural invasiveness to preserve local bloodsupply, and early and pain-free mobilization so that the patient canreturn to normal function as soon as possible. These principles haveguided the development of many examples of bone implants, such as boneplates, intramedullary nails, vertebral implants, etc., as well asscrews and or anchors configured to hold the bone implant in the desiredposition at the intended tissue site.

SUMMARY

According to an embodiment of the present disclosure, a bone fixationsystem can include a bone implant and at least one bone fixationelement. The bone implant can be elongate along a longitudinaldirection. The bone implant includes an implant body that defines anupper surface, a bone-facing surface opposite the upper surface andspaced from the upper surface along a transverse direction that isperpendicular to the longitudinal direction, at least one aperture thatextends through the implant body from the upper surface to thebone-facing surface. The at least one aperture is defined by an innerwall. The bone fixation element is configured to be inserted at leastpartially through the aperture into an underlying fixation site. Thebone fixation element defines a proximal end and a distal end spacedfrom the proximal end along a central axis in a distal direction. Thebone fixation element defines a bone fixation body having a headdisposed at the proximal end and a shaft that extends relative to thehead toward the distal end. The head defines a first ridge and a secondridge that is spaced from the first ridge along the distal direction,and a groove disposed between the first and second ridges. The groove isrecessed into the head toward the central axis between the first andsecond ridges. The groove is configured to receive at least a portion ofthe inner wall to secure the bone fixation element to the bone implant.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofillustrative embodiments of the bone fixation system of the presentdisclosure, is better understood when read in conjunction with theappended drawings. It should be understood, however, that the presentdisclosure is not limited to the precise schematics and arrangementsshown. In the drawings:

FIG. 1A is a perspective view of a bone fixation system secured to afixation site such as a bone, according to an embodiment of the presentdisclosure;

FIG. 1B is an exploded perspective view of the bone fixation systemshown in FIG. 1A;

FIG. 1C is a perspective view of a bone fixation system shown in FIG.1A, illustrating a first bone fixation element and a second bonefixation element securing a bone implant to a bone;

FIG. 1D is a cross-sectional view of the bone fixation system takenalong line 1-1 in FIG. 1A, illustrating the bone fixation elementpartially inserted in the bone implant;

FIG. 1E is a cross-sectional view of the bone fixation system takenalong line 1-1 in FIG. 1A, illustrating the bone fixation elementinserted in the bone implant;

FIG. 2A is a perspective view of the bone implant shown in FIG. 1A;

FIG. 2B is a plan view of the bone implant shown in FIG. 2A;

FIG. 2C is a cross-sectional view of the bone implant shown in FIG. 2Btaken along line 2B-2B in FIG. 2B;

FIG. 3A is a side view of the bone fixation element shown in FIG. 1A;

FIG. 3B is cross-sectional view of the fixation element taken along line3B-3B in FIG. 3A;

FIG. 4A is a sectional view of a bone implant according to analternative embodiment of the present disclosure;

FIG. 4B is a bone fixation element configured for the bone implant shownin FIG. 4A;

FIG. 5A is a sectional view of a bone implant according to analternative embodiment of the present disclosure;

FIG. 5B is a bone fixation element configured for the bone implant shownin FIG. 5A;

FIG. 6A is a sectional view of a bone implant according to analternative embodiment of the present disclosure;

FIG. 6B is a fixation element configured for the bone implant shown inFIG. 6A;

FIG. 7A is a sectional view of a bone implant according to analternative embodiment of the present disclosure;

FIG. 7B is a bone fixation element configured for the bone implant shownin FIG. 7A;

FIG. 8A is a perspective view of a bone fixation system according to analternative embodiment of the present disclosure;

FIG. 8B is a cross-sectional view of the bone fixation system takenalong line 8B-8B in FIG. 8A; and

FIGS. 9A-9J are sectional views of bone fixation systems according toother alternative embodiments of the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Referring to FIGS. 1A-1D, a bone fixation system 2 in accordance withone embodiment is configured to stabilize a bone that has been fracturedat one or more fracture locations into a plurality of bone fragments.The bone fixation system 2 includes a bone implant 4 and a bone fixationelement 6 configured for insertion at least partially through the boneimplant 4 to secure the bone implant 4 to an underlying fixation site 8.The bone fixation element 6 includes a variable dimensioned profile thatassists in advancing the bone fixation element 6 through the boneimplant 4 in a transverse direction T relative to the bone implant 4toward the fixation site 8, as well as coupling the bone fixationelement 6 to the bone implant 4 (FIG. 1E).

The fixation site 8 can be a bone as illustrated, an implant, or adevice configured to receive a bone fixation element. For instance, thefixation site 8 can be a pair of fixation sites that include a firstfixation site 8 a located on a first bone fragment 7 a and a secondfixation site 8 b located on a second bone fragment 7 b. The second bonefragment 7 b is separated from the first bone fragment 7 a by a fracturelocation FL. The fixation site 8 can be located at any anatomicallocation on a skeletal system. For instance, the fixation site 8 can belocated on the skull, the vertebral column, any long bone, such as thehumerus, femur, tibia, fibula, or any other location on the skeletonsystem where fixation is needed. The fixation site 8 can also be anadditional implant, device or prosthesis configured to receive the bonefixation element therethrough for securement to the bone.

The bone fixation element 6 is coupled to the bone implant 4 when thebone fixation element 6 is fully inserted or deployed in the boneimplant 4 as shown FIGS. 1A, 1C and 1E. The coupling between the bonefixation element 6 and bone implant 4 provides 1) angularly stabilitybetween the bone fixation element 6 and the bone implant 4, and 2) theability of the bone fixation element 6 to rotate relative to the boneimplant 4. For instance, when a plurality of bone fixation elements 6are coupled to bone implant 4 and secured to the fixation site 8,angularly stable fixation is achieved because the bone implant 4 forms astable bridging structure with the bone fixation elements 6 that spansthe fracture location FL (FIG. 1C). Further, the bone fixation element 6can be coupled to the bone implant 4 such that the bone fixation element6 can be rotated relative to the bone implant 4. For instance, in theillustrated embodiment the bone fixation element 6 is rotatably coupledto the bone implant 4 when fully deployed or seated in the implant 4 asshown in FIG. 1E. Such rotatable coupling allows the bone fixationelement 6 to rotate relative to the bone implant 4 without causingfurther advancement of the bone fixation element 6 along the transversedirection T through the bone implant 4. When bone fixation element 6 iscoupled the bone implant 4 s and the bone fixation element 6 is securedto the fixation site 8, rotation of the bone fixation element 6repositions the bone implant 4 closer to or further away from thefixation site 8 depending on the rotation direction of the bone fixationelement 6. Accordingly, the bone implant 4 can be repositioned to adesired position relative to the fixation site 8, so that, for example,the distance between the bone implant 4 and the fixation site 8 can beset to maintain an optimal blood supply near the fixation site 8 andfracture location FL. Such coupling may also improve the tactility ofinsertion of the bone fixation element 6 into the fixation site 8. Boneis generally made of two types of bone, cortical and cancellous bone.The cortical bone surrounds the cancellous bone and is relatively harderthan the cancellous bone. Since the bone fixation element 6 can berotated in the bone implant 4, the user or person applying the rotationwith, for example, a driving instrument, can feel during insertion whenthe bone fixation element 6 is advancing into relatively hard corticalbone or relatively soft cancellous bone.

Referring to FIGS. 1A and 2A-2C, the bone implant 4 defines an implantbody 10 that is elongate substantially along a central implant axis 12.The bone implant 4 can extend between a first implant end 14 (notshown), and second implant end 16 (not shown) spaced from the firstimplant end 14 along the central implant axis 12. The first and secondimplant ends 14 and 16 are not shown in FIGS. 1A-1C in order toillustrate a portion of the bone implant 4. The implant body 10 includeslateral sides 18 and 20 that are spaced from each other along a lateralimplant axis 13 or second direction that is perpendicular with respectto the central implant axis 12. In accordance with one embodiment, thecentral implant axis 12 can extend along a longitudinal direction L, andthe lateral sides 18 and 20 are spaced from each other along the lateraldirection A that is substantially perpendicular to the longitudinaldirection L. Thus, reference to the longitudinal direction L hereinrefers to the central implant axis 12, unless otherwise indicated.Further, reference to the lateral direction A herein refers to thelateral implant axis 13 or the second direction, unless otherwiseindicated. The implant body 10 can further define a bone facing surface22 and an opposed or upper surface 24 that faces away from the fixationsite 8 when the bone implant 4 is secured to the fixation site 8. Thebone facing surface 22 and the opposed surface 24 can be spaced fromeach other along a transverse direction T that is substantiallyperpendicular with respect to both the longitudinal direction L and thelateral direction A. The bone implant 4 defines a plurality of apertures26 that extend through the implant body 10 along the transversedirection T, and an inner wall 33 the extends along each aperture 26between the upper surface 24 and bone-facing surface 22. The inner wall33 can be at least partially curved along the transverse direction T.

The bone implants of present disclosure are described herein asextending horizontally along a longitudinal direction “L” and a lateraldirection “A”, and vertically along a transverse direction “T”. Unlessotherwise specified herein, the terms “longitudinal,” “transverse,” and“lateral” are used to describe the orthogonal directional components ofvarious bone fixation system components and component axes. It should beappreciated that while the longitudinal and lateral directions areillustrated as extending along a horizontal plane, and that thetransverse direction is illustrated as extending along a vertical plane,the planes that encompass the various directions may differ during use.Further, the description refers to bone fixation system componentsand/or portions of such components that include a “proximal end” and a“distal end.” Thus, a “proximal direction” or “proximally” refers to adirection that is oriented generally from the distal end toward theproximal end. A “distal direction” or “distally” refers to a directionthat is oriented generally from the proximal end toward the distal end.

Continuing with FIGS. 2A-2C, the bone implant 4 includes at least onewire 100 that is shaped to define the implant body 10 to define theplurality of apertures 26 that extend though implant body 10 along thetransverse direction T. The bone implant 4 can be partially orcompletely made of wire, which can define any implant body and aperturesize and shape as desired. The wire 100 can define a first wire segment102 and a second wire segment 104 that are shaped to define the boneimplant. The first and second wire segments 102 and 104 can be integraland monolithic to form the wire 100. Alternatively, the first and secondwire segments 102 and 104 can be separate from each other and defined bytwo different respective wires. The wire 100 defines a wire outersurface 101 that includes the bone contacting surface 22, opposedsurface 24, lateral sides 18 and 20, and the inner wall 33. The innerwall 33 can include a first inner wall 32 and a second inner wall 34.For instance, the wire 100 is shaped to define the inner walls 32 and 34that define the plurality of apertures 26 as detailed below. When thewire segments 102 and 104 are formed of two wires, the two wires definedifferent inner walls 32 and 34. When a single wire forms the wiresegments 102 and 104, one wire defines the inner wall 33. As usedherein, “inner wall 33” and “inner walls 33” are used interchangeablywith reference to the first and second inner walls 32 and 34, unlessotherwise noted. Thus, the inner wall 33 (or inner walls 32 and 34) arecurved along the transverse direction T and curved along thelongitudinal direction L. Portions of the inner walls 32 and 34 lie in aplane (not shown) that is perpendicular to the lateral implant axis 13so that the bone contacting surface 22 may lie substantially flush to abone and the opposed surface 24 faces away from the bone contactingsurface 22, and thus away from the fixation site 8. While a bone implant4 that includes a wire 100 is illustrated in FIGS. 1A-7B, the boneimplant 4 can be formed of a bone plate as shown in FIG. 8A-8B andfurther detailed below.

Continuing with FIGS. 1C, 2A-2C, the bone implant 4 defines theplurality of apertures 26 that extend though the bone implant body 10along the transverse direction T. For instance, the first and secondinner walls 32 and 34 can define each of the plurality of apertures 26that include a first aperture 26 a and a second aperture 26 b that isspaced from the first aperture 26 a along the longitudinal direction L.The bone implant 4 can include a number of apertures as needed. Thefirst and second apertures 26 a and 26 b are configured to receive bonefixation elements therein. In particular, the bone fixation element 6can be a first bone fixation element 6 that is configured for insertionin the first aperture 26 a. The bone fixation system 2 can also includea second bone fixation element 106 (FIG. 1C) that is configured forinsertion in the second aperture 26 b so as to secure a bone implant 4to the fixation site 8 and fuse the first and second bone fragments 7 aand 7 b together.

Continuing with FIGS. 2A-2C, in the illustrated embodiment the first andsecond wire segments 102 and 104 define spaced apart neck portions 108,110, 112 that at least partially define the apertures 26. The apertures26 can be elongate along the longitudinal direction L. The neck portions108, 110, 112 define respective intersection points 25 a, 25 b, 25 cwhere the first inner wall 32 and second inner wall 34 abut. The firstwire segment 102 extends along the longitudinal direction L betweenadjacent necks 108 and 110 and adjacent necks 110 and 112 to define thefirst inner wall 32. The second wire segment 104 extends along thelongitudinal direction L between the adjacent necks 108 and 110 (and 110and 112) to define the second inner wall 34. The first and second wiresegments 102 and 104 extend along the longitudinal direction L to definespaced apart longitudinal ends 28 and 30 of the apertures 26 defined bya pair of adjacent necks. Thus, each aperture 26 extends between a firstor proximal longitudinal end 28 and second or distal longitudinal end 30spaced from the first longitudinal end 28 along the central implant axis12 between adjacent intersection points 25.

As discussed above each aperture 26 extends along the inner walls 32 and34 through the implant body 10 along the transverse direction T. In theillustrated embodiment, the wire 100 or wire segments 102 and 104 have acircular cross-sectional shape such that a portion of the inner walls 32and 34 are curved with respect to the transverse direction T. The boneimplant body 10 defines a central aperture axis 38 that extends alongthe transverse direction T, an aperture lateral axis 39 a that extendsalong the lateral direction A through opposed portions of the wiresegments 102 and 104, and a second or aperture longitudinal axis 39 bthat extends through opposed first and second longitudinal ends 28 and30. The aperture longitudinal axis 39 b is coaxial with the centralimplant axis 12. In other embodiments, the aperture 26 cross-sectionalong a plane that is aligned with the central implant axis 12 can beelongate, slot-shaped, elliptical, circular or polygonal. Accordingly,the apertures 26 can be elongate along the longitudinal direction L (orelongate along the lateral direction A). When the aperture is circular,the first and second longitudinal ends 28 and 30 and the inner walls 32and 34 define a radial extremity of the aperture 26. For circularapertures (FIG. 9), the aperture lateral axis 39 a and the aperturelongitudinal axis 39 b are referred to as the aperture radial axis 39.

Continuing with FIGS. 2A-2C, the inner wall 33 of the implant body alongthe aperture 26 is at least partially threaded. In the illustratedembodiment, the first and second inner walls 32 and 34 define a pair ofopposed threaded regions that threadably engage portions of the bonefixation element 6 dependent on the axial position of the bone fixationelement 6 in the aperture 26. The pair of threaded regions include afirst threaded region 40 and a second threaded region 42 disposed onfirst and second wire segments 102 and 104, respectively. Thus, theinner wall 32 defines the first threaded region 40 and the inner wall 34defines the second threaded region 42. Each threaded region 40 and 42extends between a proximal end 44 and a distal end 46 spaced from theproximal end 44 along the central aperture axis 38. Specifically, thefirst threaded region 40 extends between a proximal end 44 a and adistal end 46 a on the first wire segment 102, and the second threadedregion 42 extends between a proximal end 44 b and a distal end 46 b onthe second wire segment 104. Further, the first and second threadregions 40 and 42 extend longitudinally along a portion of the innerwalls 32 and 34, respectively. Alternatively, the first and secondthreaded regions extend along the inner walls 32 and 34 between apertureends 28 and 30 to define single threaded region disposed on eachrespective wall 32 and 34. In the illustrated embodiment, the first andsecond inner walls 32 and 34 are convex.

Each threaded region 40 and 42 define a plurality of spaced apart peaks43 a-c and a plurality of valleys 45 a-d. Adjacent pairs of peaks 43 candefine a valley 45. The peaks define peak points that are aligned alonga curved path. For instance, the peaks are aligned along an curved pathor arc defined by the outer surface 101 of the wire 100. In particular,the peak points of the first threaded region 40 lie in a convex path.The peak points on the second threaded region 42 lie in a convex path.Each valley 45 defines a valley point and each valley point can beaxially aligned to define a line that is parallel to the centralaperture axis 38. Alternatively, each valley point lies along a curvedpath or line.

Continuing with reference to FIGS. 2A-2C, the upper surface 24 and thebone-facing surface 22 can be curved or linear. A portion of the uppersurface 24 extending from the proximal ends 44 of each threaded region40 and 42 toward the lateral sides 18 and 20 is curved or convex.Further, the portion of the bone-contacting surface 22 that extends fromthe distal ends 46 of each threaded region 40 and 42 toward the lateralsides 18 and 20 is curved or convex. While the peaks of the threadedregions lie along a convex path as shown in FIGS. 1A-2C, in alternativeembodiments the peaks of threaded regions 40 and 42 can lie along acurved path that has a curvature that is different from the curvature ofthe upper surface 24 and the bone-facing surface 22. Further, one ormore of the peaks of the threaded regions 40 and 42 may lie along a paththat is linear (FIGS. 4A-6B and 9).

Referring to FIGS. 1D, 1E and 3A-3B, the bone fixation element 6 has aproximal end 50, a distal end 52 spaced from the proximal end 50 alongan element axis 51 in a distal direction. The central axis 51 is coaxialwith the central aperture axis 38 when the bone fixation element 6 isdisposed in the aperture 26 (FIG. 1E). The bone fixation element 6 canalso define a radial axis 53 that is perpendicular to the central axis51. The bone fixation element 6 can also threadably engage a bone. Thebone fixation element 6 can be an anchor, rivet, bone pin or screwconfigured for securement to the fixation site 8. The illustrated bonefixation element 6 is a self-tapping screw. However, the skilled personwould understand that the fixation element 6 could be a screw, forexample a standard screw, that is a non self-tapping screw or aself-drilling screw.

The bone fixation element 6 can define a fixation body 54 extendingbetween the proximal end 50 and the distal end 52. The bone fixationbody 54 has a head 55 disposed at the proximal end 50 and a shaft 62that extends distally with respect to head 55. The head 55 defines afirst ridge 56, a second ridge 58 that is spaced distally from the firstridge 56 along the central axis 51, and an groove 60 between the firstridge 56 and the second ridge 58. The groove 60 is configured to receivea portion of the inner wall 33 of the bone implant 4 to secure the bonefixation element 6 to the bone implant 4. The groove 60 is recessed intothe head 55 toward the central axis 51 between the first and secondridges 56 and 58. In an the illustrated embodiment, the groove 60 isunthreaded. The bone fixation body 54 defines a proximal surface 78 thatis transverse to the central axis 51. The head 55 extends from theproximal surface 78 to a head distal end 72 that is spaced from theproximal surface 78 along the central axis 51. The head 55 also definesan outer head surface 59 that defines the outer extremity of the head55. The proximal surface 78 further defines a socket 86 that extendsinto the bone fixation body 54 along the central axis 51 toward thedistal end 52 of the bone fixation element 6. The socket 86 can have anysuitable shape to receive a tool, such as a driving instrument. Forinstance, the socket 86 can be a square, hex, cross, slot, flat, star,hexalobular, or any other suitable shape to receive a tool. Further, thebone fixation body 54 can be cannualated (not shown) from the socket 86to the distal end 52 and may include one or more transverse boresextending through the body 54 to the cannulation. The transverse boresare configured for receiving additional fixation elements therethrough,such as a temporary guidewire or Kirschner wire, or an additional screwthat can be inserted through the socket 86 and the transverse bore tosecure to a bone or an implant. The transverse bores can also allow forbone ingrowth as well. The fixation body 54 also defines a neck 66disposed between the head 55 and the shaft 62. The shaft 62 includesthreads 64 for threadably engaging the fixation site 8. The shaftthreaded portion can extend from the neck 66 distally to the distal end52 of the bone fixation element 6.

The first ridge 56 is configured to engage a portion of the bone implant4. The first ridge 56 can be generally convex with respect to thecentral axis 51 so that the first ridge extends outwardly from thecentral axis 51. Further, the first ridge 56 is circumferentiallydisposed around the head 55 along a line (not shown) that isperpendicular to the central axis 51. The first ridge 56 extends fromthe proximal surface 78 to a first ridge distal end 76 that is spaceddistally from the proximal surface 78 along the central axis 51. Thehead 55 can define a first ridge apex or first apex 74 disposed at theouter head surface 59 between the proximal surface 78 and the firstridge distal end 76. The ridge distal end 76 can mate with or abut theinner walls 32 and 34 of the bone implant 4 when the bone fixationelement 6 is inserted in the aperture 26. The first ridge 56 defines afirst ridge cross-sectional dimension D1 defined as the distance betweendiametrically opposed points of the first apex 74. The firstcross-sectional dimension D1 can range between about 1 mm and about 15mm. In an exemplary embodiment, D1 can be about 3.5 mm. When the bonefixation element 6 is fully inserted through the aperture 26, the headproximal surface 78 and a portion of the upper surface 24 lie on similara plane (not shown) that is parallel to the central implant axis 12. Inalternative embodiments, at least a portion of the first ridge 56 can belinear. Other ridge configurations are possible as described below withrespect to FIGS. 9A-9J.

The second ridge 58 is configured to threadably engage portions of thebone implant 4 depending on the axial position of the bone fixationelement 6 in the aperture 26. The second ridge 58 can be generallyconvex with respect to the central axis 51 so that the second ridgeextends outwardly from the central axis 51. The second ridge 58 iscircumferentially disposed around the head 55 along a line (not shown)that is perpendicular to the central axis 51. The second ridge 58extends between a second ridge proximal end 70 and the head distal end72 that is spaced distally from the ridge proximal end 70 along thecentral axis 51. The head 55 defines a second ridge apex or second apex158 that is disposed between the proximal end 70 and head distal end 72.The second apex 158 can be equidistant between the second ridge proximalend 70 and the head distal end 72. The second apex 158 can also beaxially aligned with the first apex 74 of first ridge 56. In alternativeembodiments, at least a portion of the second ridge 58 can be linearbetween the second ridge proximal end 70 and the head distal end 72 todefine a ridge face (not shown) that protrudes radially outward withrespect to the central axis 51. The second ridge 58 defines a secondcross-sectional dimension D2 that extends between the most radiallyoutward points shown at apex 158. The second or ridge cross-sectionaldimension D2 can range between about 1 and about 15 mm. In an exemplaryembodiment, D2 can be about 3.5 mm. As illustrated, the secondcross-sectional dimension D2 is no greater than the firstcross-sectional dimension D1 of the first ridge 56. In an exemplaryembodiment, D1 and D2 are the same. However, as the skilled person wouldof course understand, the second cross-sectional dimension D2 can beless than or greater than the first cross-sectional dimension D1 of thefirst ridge 56.

The head 55 is threaded at a location between the groove 60 and theshaft 62 so that the threads of the head 55 can threadably engage thethreaded inner wall 33 of the bone implant 4. In one embodiment, thesecond ridge 58 is at least partially threaded to engage with thethreaded regions 40 and 42 as the bone fixation element 6 is advancedthrough the aperture 26. For instance, the second ridge 58 can include athread with one or more thread peaks 154 a-c. Adjacent thread peaksdefine valleys 155 a-c. The peaks 154 are aligned along an arc definedby the head outer surface 59. In the illustrated embodiment, thread peak154 b defines the ridge apex 158. The second ridge 58 can be entirelythreaded as shown, or partially threaded. When the bone fixation element6 is fully inserted in the aperture 26 as shown in FIG. 1E the secondridge 58 threadably disengages from the pair of threaded regions 40 and42. When the thread second ridge 58 disengages, the a portion of theinner wall of the bone implant 4 is held or seated between the firstridge 56 and the second ridge 58. Because the bone implant 4 heldbetween the first ridge 56 and the second ridge 58 angularly stablefixation is achieved.

Continuing with FIGS. 2A and 2B, the groove 60 is configured to receivea portion of the bone implant 4. The head 55, or head outer surface 59,defines a groove surface 63 that extends between the first ridge 56 andthe second ridge 58. A portion of the inner wall 33 can be received bythe groove 60 between the first and second ridges 56 and 58. Forinstance, the groove 60 also extends from the first ridge distal end 76to the second ridge proximal end 70 along the central axis 51, andcircumferentially around the bone fixation body 54 with respect to thecentral axis 51. The groove 60 can define a third or groovecross-sectional dimension D3. The groove cross-sectional dimension isdefined as the distance between opposing points 65 a-b located on thegroove surface 63 lying on a plane that is perpendicular to the centralaxis 51 and spaced equidistant between the first apex 74 and second apex158. While the groove cross-sectional dimension D3 can vary as needed,the groove cross-sectional dimension D3 is no greater than either orboth of the first cross-sectional dimension D1 and the secondcross-sectional dimension D2. For example, D3 can be 3.0 mm when the D1and/or D3 is 3.5 mm as discussed above. However, it should beappreciated that D3 can vary from 3.0 mm. As discussed above, the groove60 conforms to the curved inner walls 32 and 34 such that the groove 60abuts the threaded regions 40 and 42 when the bone fixation element 6 isinserted in the aperture 26. In the illustrated embodiment, the groovesurface 63 is concave and conforms to the convex inner walls 32 and 34as well as portions of the upper surface 24 and bone-facing surface 22.In an exemplary embodiment, the concavity of the groove surface 63 has aradius of curvature that matches the radius of curvature of the innerwalls 32 and 34, or matches the curvature of the wire or a portion ofthe bone implant 4.

In alternative embodiments, at least a portion of the groove 60 islinear such that a portion of the groove surface 63 is parallel to thecentral axis 51 (FIGS. 5B and 6B) offset with respect to the first ridge56 and second ridge 58 along the radial axis 53 (FIGS. 5A and 5B).Further, the groove surface 63 can be tapered proximally from the secondridge 58 toward the first ridge 56 such that the groove 60 has across-sectional dimension that is narrow near the first ridge 56 andlarger near the second ridge 58. Alternatively, the groove surface 63can be tapered distally from the first ridge 56 toward the second ridge58 such that the groove 60 has a cross-sectional dimension that isnarrow near the second ridge 58 and larger near the first ridge 56.

To achieve coupling between the bone fixation element 6 and the boneimplant 4, the bone fixation element 6 is configured so that the groove60 and inner walls 32 and 34 fit snuggly together with minimal or nogap. The aperture 26 can have an aperture dimension 29 (FIG. 2B) that isdefined as the distance between opposing points located in each threadedregion 40 and 42 lying on a similar plane that extends through the innerwalls 32 and 34 along radial axis 53. The aperture cross-sectionaldimension 29 can range between 1-mm or and 15 mm as needed. However, theaperture cross-sectional dimension 29 can be greater than 15 mm asneeded when the apertures are configured as elongate slots.

Continuing with reference to FIGS. 1A to 1E, the neck 66 is disposedbetween the head 55 and shaft 62. The neck 66 extends between the headdistal end 72 and the proximal end 68 of the shaft 62. In theillustrated embodiment, the neck 66 is concave and extends toward thecentral axis 51. A distal portion of the head 55 and the proximal end 68of the shaft 62 define an angle α. Angle a can range between 45 degreesand 75 degrees. In one embodiment, an angle α is about 60 degrees. Theneck 66 can define a neck or fourth cross-sectional dimension D4 definedas the distance between opposed radial points (not shown) of the shaft62. The fourth cross-sectional dimension D4 is less than one or both thefirst cross-sectional dimension D1 and the second cross-sectionaldimension D2. The fourth cross-sectional dimension D4 can range between0.5 and 14.5 mm. In an exemplary embodiment, D4 can be about 1.6 mm whenD1 and D2 are about 3.5 mm. The neck 66 is configured to ease insertionof the head or second ridge 58 of the bone fixation element 6 into theaperture 26.

Referring to FIGS. 4A-7B, in accordance with alternative embodiment, thebone fixation systems include a bone implant 4 that defines an implantbody 10. The implant body 10 includes wire segments 102 and 104 thatinclude neck portions 108, 110, 112 with intersection points 25. Theimplant body 10 also defines an inner wall 33 extending along theaperture 226. The inner wall 33 defines a pair of spaced apart threadedregions 40 and 42. At least a portion of the upper surface 24 extendsfrom the proximal end 44 of each threaded regions 40 and 42 along thelateral direction A. A portion of the bone-contacting surface 22 alsoextends from the distal end 46 of each threaded region 40 and 42 alongthe lateral direction A as discussed above. Further, the bone fixationelements shown in FIGS. 4B, 5B, 6B and 7B, include a head, a shaft and aneck. The head defines a first ridge, a second ridge, and a groove. Inaccordance with the alternative embodiments, the wire 100 can havedifferent cross-sectional shapes, such as rectangular, square orelliptical shapes. Thus, the wire 100 can define aperture profiles 226,326 and 426 as shown in FIGS. 4A, 5A, and 7A.

Turning to FIG. 4A, in accordance with the alternate embodiment, theimplant body 10 defines an aperture 226 extending through the implantbody 10. The inner wall 33 includes a first inclined portion 80 thatextends from the proximal ends 44 of threaded regions 40 and 42 to theupper surface 24. The inner wall 33 can include a second inclinedportion 82 that extends from the distal ends 46 of threaded region 40and 42 to the bone-facing surface 22. The first inclined portion 80 andthe second inclined portion 82 define an angle θ therebetween. Angle θcan be a right angle or an oblique angle as needed. Referring to FIG.4B, the bone fixation element 206 includes head 255 defining a firstridge 256, a second ridge 258, and a groove 260 between the first andsecond ridges 256 and 258 that is configured to receive the inner wall33. In accordance with an alternate embodiment, the first ridge 256defines a distal face 276 that is angularly offset with respect tocentral axis 51 and forms a portion of the groove 260. The groovesurface 262 is linear along a central axis 51 from the distal face tothe second ridge 258. The distal face 276 conforms to first inclinedportion 80 when the bone fixation element 6 is inserted into theaperture 226.

Turning to FIGS. 5A-6B, in accordance with an alternative embodiment,the implant body 10 defines an inner wall 33 and an aperture 326 thatextends along the inner wall 33 and through the implant body 10. Theinner wall 33 defines a first recess 90 disposed proximally in theaperture 326, projections 91 distal to the first recess 90 andprotruding into the aperture 326 along the lateral direction A, and asecond recess 92 disposed distal to the projections 91 in the aperture326. The threaded regions 40 and 42 are disposed at the projection 91.The implant body 10 can also define a first set of vertical faces 94 aand 94 b that extend from the projection 91 to the upper surface 24along the transverse direction T. The first set of vertical faces 94 aand 94 b and a portion of the projections 91 define the first recess 90.The implant body 10 also defines a second set of vertical faces 96 a and96 b that extend distally from the projections 91 to the bone-facingsurface 22 along the transverse direction T. The second set of verticalfaces 96 a and 96 b and a portion of the projections 91 define thesecond recess 92. In accordance with an alternative embodiment as shownin FIG. 5B, the bone fixation element 306 includes a head 355 thatdefines a first ridge 356, a second ridge 358, and a groove 360 that isconfigured to mate with the profile of inner wall 33 of the bone implant4 shown in FIGS. 5A and 6A. The first ridge 356 includes a distal face376 that is transverse to the central axis 51. In particular, the firstridge 356 can fit within the first recess 90, the groove 360 receivesthe threaded regions 40 and 42, and the second ridge 358 at leastpartially fits within the second recess 92. When the bone fixationelement 6 is inserted in the aperture 326, the first ridge 356 fitswithin the first recess 90 so that the distal face 376 abuts theprojections 91 and vertical faces 94 a and 94 b.

Referring to FIGS. 7A-7B, the bone fixation system 404 includes a boneimplant 404. The bone implant 404 includes the implant body 10 with wiresegments 102 and 104 having elliptical cross-sectional shapes. The bonefixation element 406 has a groove 460 that is concave and has acurvature that conforms to curvature of the inner wall 33 defined by theelliptically shaped wire segments of the implant body 10.

Referring again to FIGS. 1A-1E, in accordance with another embodiment, amethod for coupling the bone fixation element 6 to the bone implant 4can include advancing the bone fixation element 6 through multiple axialpositions in the aperture 26. In the illustrated embodiment thepositions can include 1) a first or insertion position 11 a as shown inFIG. 1B), 2) a second or initial engagement position 11 b as shown inFIG. 1D), and 3) a third deployed or seated position 11 c as shown inFIGS. 1A and 1E.

When the bone fixation element 6 is in the insertion position 11 a, thebone fixation element 6 is aligned with the aperture 26. The bonefixation element 6 is shown aligned with the central aperture axis 38.Next, the bone fixation element 6 is advanced through the aperture 26along an insertion direction I so that that the shaft 62 passes throughthe aperture 26. The insertion direction I is aligned with the centralaxis 51 of the bone fixation element 6. A tool (not shown) can engagethe socket 86 and cause rotation of the bone fixation element 6 aboutthe central axis 51 so that the shaft 62 threadably engages the fixationsite 8. Further advancement of the bone fixation element 6 along theinsertion direction I causes the threaded second ridge 58 to threadablyengage the threaded regions 40 and 42 at the initial engagement position11 b shown in FIG. 1D. Still further advancement of the head 55 throughaperture 26 causes the bone implant 4 to seat in the groove 60 so thatthe groove 60 receives the inner walls 32 and 34 of the bone implant 4.That is, rotation of the bone fixation element 6 advances the secondridge 58 along the threaded regions 40 and 42 in the insertion directionI until the second ridge 58 threadably disengages from the threadedregions 40 and 42 (FIG. 1E). When the bone fixation element 6 is in thedeployed position 11 c, the first ridge 56 and the second ridge 58moveably couple the bone implant 4 to the bone fixation element 6. Forinstance, the bone fixation element 6 can be further rotated so as toreposition the bone implant 4 along the transverse direction T relativeto the fixation site 8. Thus, rotation of the bone fixation element in afirst rotational direction (not shown) can reposition the bone implant 4closer to the fixation site 8. Rotation of the bone fixation element 6along second rotation direction (not shown) that is opposite to thefirst rotational direction can reposition the bone implant 4 furtheraway from the fixation site 8. Accordingly, the distance between thebone implant 4 and the fixation site 8 can be adjusted when the bonefixation element 6 is coupled to the bone implant 4. Further, when thebone implant 4 includes elongate apertures, the bone implant 4 can bereposition relative to the fixation site along a lateral directionand/or longitudinal direction L. That is, the bone implant 4 canreposition so that the bone fixation element 6 translated along theinner walls of the aperture 26 until the bone implant 4 is in desiredposition.

Referring to FIG. 1C, in accordance with an alternate embodiment, themethod can included coupling an additional bone fixation element to thebone implant 4. For instance, the bone fixation system can include thesecond bone fixation element 106. The second bone fixation element 106can be inserted through the second aperture 26 b so that the groove 160(not shown) receives the bone implant 4 in a manner similar to how thefirst bone fixation element 6 is inserted in the first aperture 26 adescribed above. While the first and second bone fixation elements 6 and106 can be configured similarly as described in the present disclosure,the first and second bone fixation elements can be different types ofbone fixation elements. For instance, the bone fixation element 6 can beconfigured as described herein to moveably couple with the bone implant4, and the second bone fixation element 106 can be a conventionallocking screw, non-locking screw, a compression screw, variable anglescrew, or another other type of bone fixation element.

Referring to FIG. 8A, the bone fixation system 502 can include a boneimplant 504 and a bone fixation element 506 configured to couple withthe bone implant 504. The bone implant 504 can include a bone plate body510. In the embodiment illustrated in FIG. 8A and 8B, the plate body 510can be a monolithic plate body or comprises multiple plate segments. Theplate body 510 can extend between an upper surface 524 and a bone-facingsurface 522 spaced from the upper surface 524 along the transversedirection T. The plate body 510 can define an inner wall 533 thatfurther defines the aperture 526 that extends through the plate body 510along the transverse direction T. The inner wall 533 is at leastpartially threaded to engage with the bone fixation element as describedabove. The bone implant 504 defines a central aperture axis 38 (notshown). The inner wall 533 defines a first recess 588 positionedproximally in aperture 526 toward the upper surface 524, a protrusion590 distal to the first recess 588, and a second recess 589 disposeddistal to the protrusion 590 in the aperture 526. The protrusion 590extends into the aperture 526 along a lateral direction A to define aprotrusion face 591. The protrusion 590 also extends along thetransverse direction T between a protrusion proximal face 592 and aprotrusion distal face 594. The proximal and distal faces 592 and 594can be inclined or curved. In the illustrated embodiment, the protrusionface 591 is threaded similar to the threaded regions 40 and 42 discussedabove. However, portions of the recesses can be threaded as well.Further, the protrusion can include a pair of opposed threaded regionsthat are circumferentially spaced from each other on the inner wall 533.Alternatively, the protrusion can 590 can define a single threadedregion. The inner wall 533 also defines a first vertical face 595 thatextends from the proximal face 592 of the protrusion 590 and is parallelto the aperture axis 538. The vertical face 595 and proximal face 592define the first recess. The inner wall 533 also define a secondvertical face 596 that is parallel to the aperture axis 538 and extendsfrom the distal face 594 of the protrusion 590 to the bone-facingsurface 522. The second vertical face 596 and distal face 594 of theprotrusion 590 define the second recess 588. The aperture 526 has across-sectional dimension E, which is the distance between a pair ofopposed points (not shown) located on the protrusion terminal end 591.

Continuing with FIG. 8B, the bone fixation element 506 includes fixationbody 554 having a head 555 and shaft 562 extending distally with respectto the head 555. The head 555 includes a first ridge 556, a threadedsecond ridge 556 and a groove 560 extending between the first ridge 556and the threaded second ridge 556. The first ridge 556 is configured tobe received by the first recess 588 of the plate body 510, the groove560 is configured to conform to or receive the protrusion 590, and thesecond ridge 556 is configured to be disposed at least partially in thesecond recess 589 of the plate body 510. The groove 560 defines across-sectional dimension F, which is the distance between a pair ofopposed points located on the outer surface 563 of the groove 560. Thebone fixation system 502 is configured so that the groovecross-sectional dimension F is less than the aperture cross-sectionaldimension E. That is, a gap 61 extends between the groove 560 and theprotrusion terminal end 591. The gap 61 permits the bone fixationelement 506 with respect to the bone implant 504. The aperturecross-sectional dimension E can be greater than the groovecross-sectional dimension D3 to define a gap distance G (not shown). Thegap distance G can be 0 (zero) or near 0 (zero) when the groove 560 isconfigured to abut the inner walls 32 and 34, or greater than 0 (zero)when the groove 560 and inner walls 32 and 34 define the gap 61. In oneembodiment, the gap distance G can be up to about 0.3 mm. Thus, the gap61 can be constant along the groove surface 563. However, the gap 61 canalso vary depending on the configuration of the groove 560. Forinstance, the gap 61 near the first ridge 556 can be larger than the gap61 near the second ridge 558 when the groove 560 is tapered proximallyfrom the second ridge 558 toward the first ridge 556. Alternatively, thegap 61 can be larger near the second ridge 558 compared to the gap 61near the first ridge 556 when the groove 560 is tapered distally fromthe first ridge 556 toward the second ridge 558.

In accordance with an alternative embodiment, the head 555 of the bonefixation element 506 can include threads at location between the groove560 and the shaft 562 that can threadably engage the threadedprotrusions 590 when the bone fixation element is advancing through theaperture 526. As the groove 560 advances through the aperture 526, thethreads on the head 555 threadably disengage from the threadedprotrusion 590.

While the bone fixation element 506 is illustrated coupled to the boneplate body 510, the bone fixation element 506 is configured for couplingto the bone implant 4 described above and shown in FIGS. 1A-7B. Further,the bone fixation element 6 as described above is configured forcoupling to the bone plate body 510 shown in FIGS. 8A and 8B.

Referring to FIGS. 9A-9J, in accordance with alternative embodiments ofthe present disclosure, various embodiments of a bone fixation elementare illustrated in the deployed position in the bone implant 4. The boneimplants 4 include an implant body 10 having wire segments 102 and 104that define apertures as discussed above. The implant body 10 shown inFIG. 9A-9J can also include a bone plate that defines apertures asdescribed and shown in FIGS. 8A and 8B. Specifically, any of the bonefixation elements illustrated in FIGS. 9A-9J can be coupled to any ofthe bone implants 4 and 504 described above and shown in FIGS. 1A-8B.Accordingly, the bone fixation elements can include a head 55, a shaft62, and a neck 66 between the head 55 and the shaft 62, as describedabove. The head 55 includes a first ridge 56, a groove 60 having agroove surface 63, and a second ridge 58. The implant body 10 caninclude the curved inner wall 33.

Referring to FIGS. 9A, in accordance with an alternative embodiment, thebone fixation element 606 includes a groove 60 that is concave andconforms with a portion of the wire segments 102 and 104. The firstridge 56 and second ridge 58 can have similar cross-sectionaldimensions. The inner wall 33 (not shown) is unthreaded and the head 55is unthreaded.

Referring to FIG. 9B, the bone fixation element 706 includes a head 55with a tapered groove 60. The first ridge 56 has a first cross-sectionaldimension 710 that is greater than a second cross-sectional dimension712 of the second ridge 58. Thus, the groove 60 is distally tapered fromthe first ridge 56 toward the second ridge 58. The groove 60 receivesthe inner wall 33 and extends over a portion of the upper surface 24along the lateral direction A toward opposing sides 18 and 20 (notshown). Further, the head 55 of the bone fixation element 706 isunthreaded and the inner wall (not shown) of the bone implant 4 isunthreaded.

In FIG. 9C, the bone fixation element 806 includes a first ridge 56 andsecond ridge 58 is configured so that the groove 60 extends over atleast a majority of inner walls 32 and 34. The implant body 10 can beresiliently flexible. In particular, the wire 100 is flexible so thatthe first and second wire segments 102 and 104 can be flexed or biasedto facilitate insertion of the bone fixation element 6 through theaperture 26. Thus, the implant body 10 can be flexed or biased from aninitial unbiased configuration as shown in FIG. 9C to a biased or flexedposition (not shown) where the wire segments 102 and 104 separate alongthe lateral direction A so as to increase the size and dimension of theaperture 26. The second ridge 58 extends from distal end 864 of thegroove surface a distal face 859 and projects outwardly with respect tothe neck 66. The second ridge 58 can be used to help bias the wiresegments 102 and 104 apart during insertion of the fixation element 806through the aperture.

Turning to FIGS. 9D, the bone fixation element 906 includes a proximalsurface 78. The bone fixation element 906 is configured so that when thebone fixation element 906 is fully inserted through the aperture 26, aportion of the proximal surface 78 protrudes through a plane P (notshown) that is parallel to the lateral implant axis 13 and contains anupper most portion of the upper surface 24. Further, as shown in FIG.9D, the groove 60 receives the inner walls 32 and 34 and extends over aportion of the upper surface 24.

In FIG. 9E, the head 55 of the bone fixation element 1006 includes afirst ridge 1056 that defines a lip 174 that extends along the innerwalls 32 and 34 and the upper surface 24. The ridge 1056 can apply aforce to the implant body 10 along the transverse direction T toward thefixation site 8.

Referring to FIG. 9F, the bone fixation element 1106 can be formed of atleast one wire 1101. The wire 1101 can be coiled so as to define a bonefixation body 1154 that includes a head 1155 and shaft 1162 extendingdistally form the head 1155. The head 1155 can also include a firstridge 1156, second ridge 1158, and a groove 1160 disposed between thefirst and second ridges 1156 and 1158. One or more wires segments candefine the first ridge 1156, the second ridge 1158, and the groove 1160.

Turning to FIG. 9G, the bone fixation element 1206 is configured as avariable angle bone fixation element. For instance, the fixation body 54defines a groove 1260 that extends between the first ridge 56 and thesecond ridge 58. The groove 1260 includes a plurality of groove segments67 a-c. For instance, the fixation body 54 can include a first groovesegment 67 a adjacent to the first ridge 56, a second groove segment 67b distal to the first groove segment 67 a, and third groove segment 67 cdistal to the second groove segment 67 b and adjacent to second ridge58. While three groove segments are shown, groove 1260 can include twogroove segments or more than three groove segments. The groove 1260 iscircumferentially disposed around the fixation body 54, and alignedalong a plane that is transverse or perpendicular to the central axis51. Thus, each groove segment 67 a-c is circumferentially disposedaround the fixation body 54 and aligned along a plane that is transverseor perpendicular to the central axis 51. Each groove segment 67 a-cextends between adjacent apex points 69 a-d. The head 55 extends fromthe proximal surface 78 to apex point 69 d. As discussed above, theaperture 26 includes a central aperture axis 38. The inner walls 32 and34 include threaded regions 40 and 42 (not shown). The bone fixationelement 1206 can be inserted through the aperture 26 such that the aportion of the second groove segment 67 b is engaged with or coupled tothe threaded region 40 and the spaced apart third groove segment 67 c isengaged with or coupled to the opposing threaded region 42. The threadedregions 40 and 42 are disposed along or on a similar plane, however, thespacing between the second groove segment 67 b and the third groovesegment 67 c are such that the central axis 51 is offset from thecentral aperture axis 38 at an angle θ. Angle θ is an angle defined bythe central axis 51 and the implant body lateral and/or central implantaxes 12. Angle θ can be a right angle, for instance when the secondgroove segment 67 b is engaged with both threaded regions 40 and 42.Further angle θ can be oblique as shown in FIG. 9G.

Referring to FIGS. 9H and 9I, the bone fixation system 2 can include abone fixation element configured as a locking screw 1306 as shown inFIG. 9H, or a compression screw 1406 as shown in FIG. 9I. The lockingscrew head 1355 includes threaded region 1360 that tapers linearlytoward the shaft 62. The threaded region 1360 threadably engages withthe threaded regions 40 and 42 (not shown) of the implant body 10 in theaperture. The head 1355 defines a proximal surface 78 that is generallyaligned with the upper surface 24 of the bone implant 4 when the lockingscrew 1306 is deployed in the aperture 26 and secured to the fixationsite 8. Referring to FIG. 9I, the compression screw 1406 can include ahead 1455 disposed proximally with respect to the shaft 62. The head1455 is convex and includes threads to engage with the wire segments 102and 104 of the implant body 10.

As shown in FIG. 9J, the bone fixation system 2 includes bone implant 4,and bone fixation element 1506 and a clip member 120 disposed in theaperture 26 between the bone fixation element 1506 and the bone implant4. The bone fixation element 1306 is configured so that upon insertioninto the aperture 26 the fixation body 54 is spaced from the implantbody 10 to define a gap 130 extending therebetween. The clip member 120is configured to span the gap 130 between the bone fixation element 6and the implant body 10. The bone implant body 10 can define an aperture26 as described above that includes an upper surface 24, threadedregions 40 and 42, and bone-facing surface 22 that are curved, or convexas shown. The clip member 120 can define an annular shaped clip body 122having a bore 124 extending through the clip body 122 along thetransverse direction T. The bore is sized and dimensioned to receive thehead 55 of the bone fixation element 1506 therein. The clip body 122defines an outer surface 125 that is concave and conforms to the convexshaped aperture 26.

Another embodiment of the present disclosure is a surgical kit includinga plurality of bone implants 4, and a plurality of bone fixationelements 6 configured to couple with the bone implants 4. The kit caninclude one or more bone implants 4 that include a wire as describedabove, and one or more bone implants that include a plate. The pluralityof bone fixation elements can include one or more bone fixation element6 as described above, locking screw, compression screw, variable anglescrew, or any of type of bone fixation element. The kit may also includea drill and a drill guide. The drill guide (not shown) may have athreaded end configured for insertion into the apertures of the boneimplant 4, so that a drill (not shown) can be use to pre-drill a holeinto which the bone fixation elements 6 can inserted.

The bone fixation system can be formed using any suitable biocompatiblematerials or combination of the materials. For instance, the boneimplant 4 and plates 510 can be formed of metallic materials such ascobalt chromium molybdenum (CoCrMo), stainless steel, titanium, titaniumalloys, magnesium, glass metals, ceramic materials, and polymericmaterials include plastics, fiber reinforced plastics, polymericmaterials that include polyetheretherketone (PEEK),polyetherketoneketone (PEKK), and bioresorbable materials or shapememory materials. In one embodiment, the bone implants can be formed ofa combination of polymeric and metallic materials. For instance, thebone implant 4 can be formed of polymeric wires, metallic wires, or acombination of polymeric and metallic wires. The bone implants 4 and 504may be coated an antibacterial coating, drug-eluting coating, or surfacemodifier such as a carbon diamond coating. In another example, the boneimplants 4 and 504 may be chemically processed using, for example,anodization, electropolishing, chemical vapor deposition, plasmatreatments, or any process to modify or enhance bone implant surfacecharacteristics. The bone fixation elements can also be formed of formedof metallic materials such as cobalt chromium molybdenum (CoCrMo),stainless steel, titanium, titanium alloys, nitinol and Gummetal®,magnesium, glass metals, ceramic materials, and polymeric materialsinclude plastics, fiber reinforced plastics, polymeric materials thatinclude polyetheretherketone (PEEK), polyetherketoneketone (PEKK), andbioresorbable materials or shape memory materials. The bone fixationelements can also be metallic or formed of metallic alloys, such astitanium. The bone fixation element can also be formed of a combinationof polymeric and metallic materials. For instance, the bone fixationelement can have a polymeric head and metallic shaft. The bone fixationelements may be coated an antibacterial coating, drug-eluting coating,or surface modifier such as a carbon diamond coating. In anotherexample, the bone fixation elements may be chemically processed using,for example, anodization, electropolishing, chemical vapor deposition,plasma treatments, or any process to modify or enhance bone fixationelement surface characteristics

Although the disclosure has been described in detail, it should beunderstood that various changes, substitutions, and alterations can bemade herein without departing from the spirit and scope of the inventionas defined by the appended claims. Moreover, the scope of the presentdisclosure is not intended to be limited to the particular embodimentsdescribed in the specification. As one of ordinary skill in the art willreadily appreciate from the processes, machines, manufacture,composition of matter, means, methods, or steps, presently existing orlater to be developed that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein that may be utilized according to the presentdisclosure.

1. (canceled)
 2. A method of attaching a fixation element to an implant,the method comprising: inserting a shaft of the fixation element betweenrespective inner surfaces of first and second wire segments of theimplant along a transverse direction, wherein 1) the inner surfaces arecurved as they extend along the transverse direction and define a firstthreaded region, and 2) the fixation element defines a head and theshaft extends from the head in a distal direction along a central axisof the fixation element; further inserting the fixation element betweenthe inner surfaces along the transverse direction so as to cause asecond threaded region of the fixation element to threadedly engage thefirst threaded region; and further inserting the fixation elementbetween the inner surfaces along the transverse direction until 1) thesecond threaded region is disengaged from, and spaced in the distaldirection from, the first threaded region, and 2) the first threadedregion is aligned with an unthreaded groove of the head along a lateraldirection that is perpendicular to the transverse direction, wherein thegroove extends along the transverse direction between a 1) first ridgeof the head, the first ridge extending out with respect to the centralaxis, and 2) a second ridge of the head, the second ridge extending outwith respect to the central axis and defining the second threadedregion.
 3. The method of claim 2, further comprising placing an exteriorsurface of the implant adjacent a bone such that the transversedirection intersects the bone.
 4. The method of claim 3, furthercomprising driving the shaft of the fixation element into bone during atleast one of the inserting steps.
 5. The method of claim 4, furthercomprising retaining the inner surfaces of the first and second wiresegments within the groove after the second threaded region isdisengaged from, and spaced in the distal direction from, the firstthreaded region.
 6. The method of claim 5, further comprising, after theretaining step, repositioning the fixation element relative to the bonealong the central axis so as to responsively reposition the implantrelative to the bone relative to the transverse direction.
 7. The methodof claim 6, wherein repositioning the fixation element comprisesrotating the fixation element so as to drive the fixation element intothe bone so as to reduce a space between the implant and the bone in thetransverse direction.
 8. The method of claim 6, wherein repositioningthe fixation element comprises rotating the fixation element so as toback the head of the fixation element away from the bone so as toincrease a space between the implant and the bone in the transversedirection.
 9. The method of claim 5, wherein: the first ridge has aproximal end and a distal end spaced from the first ridge proximal endalong the central axis, and the method further comprises abutting thedistal end of the first ridge against at least one of the inner surfacesof the first and second wire segments after the second threaded regionis disengaged from, and spaced in the distal direction from, the firstthreaded region.
 10. The method of claim 5, wherein: the second ridgehas a proximal end and a distal end spaced from the second ridgeproximal end along the central axis, and the method further comprisesabutting the proximal end of the second ridge against at least one ofthe inner surfaces of the first and second wire segments after thesecond threaded region is disengaged from, and spaced in the distaldirection from, the first threaded region.
 11. The method of claim 5,wherein the first threaded region comprises threads having peaks thatlie in a convex path along the transverse direction.
 12. The method ofclaim 11, wherein the threads have valleys positioned between adjacentpeaks along the transverse direction, wherein the valleys lie on alinear path along the transverse direction.
 13. The method of claim 2,wherein the first ridge is unthreaded.
 14. The method of claim 2,wherein the inner wall is curved along a longitudinal direction that isperpendicular to the transverse and lateral directions.
 15. The methodof claim 2, wherein the first and second wire segments each have asubstantially circular cross section.
 16. The method of claim 2, whereinthe first ridge defines a first cross-sectional dimension betweendiametrically opposed, radially outermost points of the first ridge, andthe second ridge defines a second cross-sectional dimension betweendiametrically opposed, radially outermost points of the second ridge,and the second cross-sectional dimension is no greater than the firstcross-sectional dimension.
 17. The method of claim 2, wherein at least aportion of the groove is curved along the transverse direction.
 18. Themethod of claim 2, wherein the groove is concave.
 19. The method ofclaim 2, wherein, when the first threaded region is aligned with theunthreaded groove along the lateral direction, the groove and at leastone of the inner surfaces defines a gap extending therebetween in thelateral direction.
 20. The method of claim 2, wherein the inner surfaceseach define a protrusion along the lateral direction, and the firstthreaded region is disposed on at least a portion of the protrusion. 21.The method of claim 2, wherein the inner surfaces each include a portionthat extends linearly along the transverse direction.